Results for: Superh

Answer for English units, see this table http://energy.sdsu.edu/testcenter/testhome/Test/solve/basics/tables/tablesPC/superR134a-Eng.html (click on SI once t…here for SI units if needed). If you need higher pressure than 400psia or 16MPa, you will need the R143a superheated vapor chart, which I can't find online. You can find tables and charts in various thermodynamics textbooks. For example, Tables in "fundamentals of engineering thermodynamics" by Moran and Shapiro; or the chart by "SUVA/DuPont" is in the appendix of the "mechanical engineering reference manual" by Lindeburg.(MORE)

Radon, a radioactive inert gas, will, when superheated, begin thermionic emission. Let's put some in a container we can see through (with nothing else to interfere) and heat i…t up. Ready? Let's do it. Electrons most loosely bound to the radon nucleus will move to the next higher available Fermi energy level (meaning the atom will ionize), and then the electrons will fall back to their original energy levels with the emission of a photon. The radon will be glowing - emitting light. The phenomenon will be repeated; more and more atoms of radon will become involved in the process. At first the light will be in the infrared spectrum and we will not be able to see it unaided. At higher heats, electrons are driven to higher and higher energy levels, and when they "fall back" into their orbitals, the will emit shorter and shorter wavelengths (higher and higher frequencies) of light in making the transition. Some reds, oranges, yellows and other colors on up the frequency spectrum will be given off by the glowing gas, but not necessarly all the colors. Radon is an unstable (radioactive) inert gas. And it has a short half-life. Let's assume that no radioactive decay occurred during our little experiment. We wouldn't want to have to deal with any of the radioactive daughters of radon that might appear and "mess up" our light show. If the question spoke to the shortening of the half-life of radon by superheating it, that is, if you want to make radon undergo radioactive decay faster by superheating it, set that notion aside. You can't affect its rate of decay by superheating radon. Oddly, almost all isotopes of all elements show a uniform resistance to having their half-lives changed by superheating them. We find little to no evidence of changes in half-lives of radioisotopes in stars, which are massive spheres of plasma that are hot almost beyond imagining. (MORE)

Saturated steam occurs when steam and water are in equilibrium. If you have a closed container of water and heat it, above 100 celsius the steam pressure will start to rise, a…nd as the temperature continues to rise, the pressure will go on rising. What is happening is that steam is being evolved to match the temperature (steam tables will give this relation) and the steam conditions are said to be saturated because if the pressure is raised by external means, some of the steam will start to condense back to water. If the steam pressure is held at a lower level than that achieved at saturation, by taking steam off to feed a turbine or other steam usage, there is effectively an excess temperature for that pressure, and the steam is said to be superheated. It in fact then becomes dry, and behaves as a gas. The amount of superheat can be quantified as so many degrees of superheat (celsius or fahrenheit). Turbine designers want steam to be superheated before reaching the turbine, to avoid condensation causing blade erosion, and steam producing boilers in power plants are designed to produce superheated steam. In plants where no turbines are used, only satured steam is normally generated. In heating applications, saturated steam is preferable, because it has a better energy exchange capacity. Superheated steam must cool down, and become saturated steam, before condensing in a heat exchanger. Also, superheated steam is a thermal insulator, like air. That is why it is necessary to direct superheated steam through a desuperheater before using the steam in heating applications. (MORE)

superheated steam produces greater pressure and power and can go very long distances by itself compared to regular steam. +++ Not quite. The pressure is no more than tha…t at which it was generated in the boiler, because it is flowing through the superheater to the engine (reciprocating or turbine) - and indeed may be less if throttled through the regulator on the boiler outlet first. I'm not sure where "distance" comes from, but superheating raises the efficiency rather than power, by keeping the steam above its condensation temperature for the instantaneous pressure it passes through in expanding to do its work. This means it can act as a gas for a longer part of the piston stroke, or for further in its route through the many stages of a steam-turbine. (MORE)

you don't have enough information to answer that question. Superheated steam only tells us that the water has been completely changed to steam and is at some temperature beyo…nd that point (at atmospheric pressure, above 100 C). What you've said doesn't give any information on pressure, pipe size, pumps, or anything else. Superheated steam could be moving at the speed of sound or going nowhere depending on conditions. (MORE)

Superheating means to heat something above its boiling point without the formation of bubbles of vapor (without it actually boiling). It can be prevented by placing someth…ing into what you are trying to cook to diffuse its energy. (MORE)

As you'll know, the amount of energy you can get from (say) steam, is limited by the difference between the hottest the steam is, and the condensation temperature. So if we …confine the steam, we can heat it well above the usual boiling point, and thus the quantity of energy we can extract is greater. (MORE)

Expansion of steam in either the saturated or superheated state is generally not isothermal. When steam expands from a high pressure to a lower pressure the temperature wi…ll be reduced, unless energy is added during the process. When steam expands in an engine such as a steam turbine, the temperature reduction is greater than during free expansion (MORE)